Orientation device, particularly for drilling tool or a well equipment

ABSTRACT

An orientation device, particularly for drilling tools, of the kind comprising a first sleeve (1) and a concentrically surrounding second sleeve (2), where in an annulus between the sleeve (1) and the sleeve (2) is disposed an axially displaceable carrier, e.g., in the form of a wedge/key (5) or a rail (8, 9), adapted to slide in an inclined, preferably helical groove (3, 4) disposed in the sleeve (1) or in the sleeve (2), the groove&#39;s direction crossing the direction of the carrier&#39;s (5; 8, 9) rectilinear movement which, thus, is converted into a relative rotational movement between the sleeve (1) and the sleeve (2). The carrier (5; 8, 9) is adapted to slide in two inclined, preferably helical grooves (3, 4) disposed in the sleeve (1) and the sleeve (2), respectively, and crossing the direction of the carrier&#39;s (5; 8, 9) rectilinear movement from opposite side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT Application No. PCT/NO97/00034filed Feb. 5, 1997 which claims priority from Norwegian PatentApplication NO. 960641 filed Feb. 19, 1996.

The invention relates to an orientation device, particularly for adrilling tool or a well equipment in oil or gas wells, of the kindcomprising a first sleeve and an axially displaceable carrier, e.g. inthe form of a wedge or a rail adapted to slide in an inclined,preferably helical groove formed in first sleeve, the groove directioncrossing the direction of the rectilinear movement of the carrier, saidmovement, thus, being converted into a rotational movement of firstsleeve.

During the drilling of oil and gas wells, a bent transition piece isoften used, in English designated "bent sub", between the bit and thedrill string, in order to achieve a directional deviation between theaxis of the drill string and the axis of the bit. Upon rotation of thebent transition piece or sub, the bit may be brought to point in thedirection in which one desires to drill.

It has been found difficult to make the bit pointing in the desireddirection through a rotation of the drill string and, when usingcoilable tubing, it is not possible to orientate the bit in that way.Therefore, it is usual to dispose a downhole orientation device which isguided and controlled from the surface, in order to rotate the benttransition piece or sub and to bring the bit to point in the desireddirection.

There exists a plurality of various types of devices for this purpose. Acommon feature of these known devices is the conversion of a rectilinearmovement into a rotational movement. This is appropriate because of theease to convert the hydraulic force available through drill fluid into acontrolled rectilinear movement by displacing a hydraulic piston.

U.S. Pat. No. 4,286,676 deals with a tool for use with directionaldrilling, wherein a carrier is adapted to slide in a groove, in order tocreate rotation of a sleeve.

Another usual way of converting a rectilinear movement into a rotationalmovement is to use some form of screw-nut combination, frequentlydisposed such that a carrier in the form of a wedge or a wedge-likemeans slides in a helical groove.

In order to convert a linear movement into a rotational movement byleans of a helical thread, the pitch of the helical thread must be sogreat that self-bloc ing or self-locking is avoided. The limit value ofthe pitch for self-blocking depends on the friction. In practice, it hasbeen found that the requirement for torsional moment is the dimensioningfactor in these cases. In order to obtain a sufficient torsional moment,the pitch of the helical thread must also be large.

However, a large pitch angle causes that the rectilinear movement neededin order to achieve a given rotational angle, becomes longer. Knownorientation devices are unappropriately long, shorter constructionalmeasures being desired.

The object of the invention is to provide an orientation device having asubstantially shorter constructional length than prior art tools.

The object is achieved through features as defined in the followingclaims.

In the following, the invention is described by means of two exemplaryembodiments, reference beign made to attached drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section of a simplified orientation device;

FIG. 2 shows, partly in section, partly in side elevational view, thesame simplified orientation device as in FIG. 1;

FIG. 3 shows a sketch of principle of the orientation device'sturn-mechanism for three rotational positions;

FIG. 4 shows in a side elevational view a sketch of principle of a wedgemeshing with two crossing grooves;

FIG. 5 shows in a top plan view the same wedge as in FIG. 4;

FIG. 6 shows in a side elevational view, partly in section, aturn-mechanism in an orientation device;

FIGS. 7 and 8 show in sectional views the upper and lower half,respectively, of an orientation device.

In FIG. 1, the reference numeral 1 denotes a first sleeve constitutingthe core of an orientation device. First sleeve 1 is surrounded by aconcentrical, second sleeve 2. In the external face of first sleeve 1, ahelical groove 3 is disposed. In the internal face of second sleeve 2, ahelical groove 4 is disposed, the latter groove 4 having the same pitchangel as the groove 3, but extending in the opposite helical direction.First sleeve 1 and second sleeve 2 are orientated such that the grooves3, 4 are crossing each other and, within the crossing area, a movablewedge 5 is placed adapted to slide in both grooves 3, 4. The wedge 5 isassigned an operating rod 6 which is connected to an actuator, notshown, and adapted to displace the wedge 5 along a straight lineparallel to the axis of first sleeve 1 and second sleeve 2, such asmarked by means of an arrow a in FIG. 2.

When the wedge 5 is displaced, first sleeve 1 rotates an angle which isdependent on the pitch angel of the groove 4. Second sleeve 2 rotatessimultaneously a corresponding angel in the opposite direction. Thus,the angular change between first sleeve 1 and second sleeve 2 becomestwice as large as the rotational angel for each of them. FIG. 3 showsdiagrammatically the two grooves 3 and 4 in three different positionscorresponding to the wedge 5 occupying three different levels.

By maintaining second sleeve 2 stationary, i.e. preventing it fromrotating, and simultanelously disposing the operating rod 6 and theactuator, not shown, belonging thereto, rotatably about the common axisof first sleeve 1 and second sleeve 2, the entire angular change canpass to first sleeve 1. The wedge 5, the operating rod 6 and theactuator, not shown, will rotate an angel decided by the pitch angle ofthe groove 4 and how far the wedge 5 is displaced. Simultaneously, firstsleeve 1 will be rotated in relation to the wedge 5 an angle determinedby the pitch angle of the groove 3 and how far the wedge 5 is displaced.Thus, a twice as large rotational angle is achieved based on a givenpitch of the helical grooves 3, 4 as wall as a given displacement of thewedge 5 as compared with known orientation devices. Thus, the samerotational angle as for known orientation devices can be obtained, usinghalf the constructional length thereof in combination with theorientation device according to the invention.

In order to avoid a too high point load in the contact face where thewedge 5 rests against the side face of the grooves 3, 4, the contactface can be increased by forming the wedge 5 with an elongate wideningat each end, e.g. such as the wedge 5' in FIG. 4 and FIG. 5.

In order to increase the contact face between wedge 5 and groove 3, 4further and simultaneously distribute loads on first sleeve 1 and secondsleeve 2, more grooves may advantageously be disposed, parallel to thegrooves 3, 4 in first and second sleeve 1, 2, respectively.Simultaneously, more wedges 5 assigned operating rods 6 must be disposedcorrespondingly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In a preferred embodiment of an orientation device, instead of the wedge5, the wedge 5', possibly several wedges 5, 5' having operating rods 6belonging thereto, a rotatable, third sleeve 7 has been disposed in theannulus between first sleeve 1 and second sleeve 2. The sleeve 7 isprovided with several internal and external helical rails 8 and 9,respectively, parallel to and engaging into a plurality of grooves 3 and4. Displacing third sleeve 7 axially, provides the same effect asalready explained in connection with the wedge 5. If second sleeve 2 iskept stationary while third sleeve 7 is displaced, third sleeve 7 willsimultaneously as it is displaced, rotate about the axis of the firstsleeve 1 a certain angle given by the displacement of third sleeve 7 andthe pitch angle of the grooves 4. First sleeve 1 will rotate through alarger angle detemined by third sleeve's 7 displacement and the pitchangle of the grooves 3, 4. If the grooves 3, 4 have the same pitchangle, first sleeve rotates twice as large an angel as third sleeve 7.Third sleeve 7 is assigned an annular piston 10 adapted to slidesealingly against first sleeve 1 and second sleeve 2 in the annulusbetween the sleeves 1, 2, the piston 10 being provided with packers 11,12. The piston 10 may be formed as a continuation of third sleeve 7 andas a part thereof, see FIG. 6. Upon the supply of hydraulic pressurizedfluid into the annulus, at one side or the other of the piston 10, thepiston 10 and the third sleeve 7 may be displaced in the annulus,causing the rotation of the first sleeve 1 in the desired direction.

FIGS. 7 and 8 show in sectional view an assembly of upper and lowerhalf, respectively, of an orientation device. As mentioned, first sleeve1 constitutes the core of the orientation device and is adapted toconduct drill fluid through the orientation device. First sleeve 1 issurrounded by second sleeve 2 and, in the annulus between the sleeves 1and 2, is placed an axially displaceable, third sleeve 7 having helicalinternal and external rails 8, 9, engaging into grooves 3, 4 in theouter face of first sleeve 1 and the inner face of second sleeve 2,respectively. When third sleeve 7 is displaced, the sleeves 1, 2 arerotated in relation to each other, such as previously described.

At the upper end, first sleeve 1 is rotatably and pressure-tightlymounted in an upper and piece 13, two annular packers 14, 15 and aradial bearing 16 being disposed in the contact face between firstsleeve 1 and end piece 13. Second sleeve 2 is stationarily andpressure-tightly connected to the end piece 13 by means of threads 17and a packer 18. A substantially axially directed channel 19 in the wallof the end piece 13 is adapted to communicate with a substantiallyaxially directed channel 20 in the wall of first sleeve 1, both channels19, 20 opening out between the packers 14 and 15. Further, the channel20 opens out in the annulus between the sleeves 1, 2 below the piston10, so that hydraulic pressurized fluid can be passed through thechannels 19, 20 to beneath the piston 10, in order to push the piston 10and, thus, third sleeve 7 upwardly. A substantially axially directedchannel 21 in the wall of the end piece 13 opens out in the annulusbetween first sleeve 1 and second sleeve 2 above the piston 10, so thathydraulic pressurized fluid can be passed through the channel 21 toabove the piston 10, in order to push the piston 10 and, thus., thirdsleeve 7 downwardly. As previously known, the end piece 13 is adapted tobe connected to a drill pipe, not shown, typically a coilable tubing, sothat the channels 19, 21 can be coupled to hoses for hydraulicpressurized fluid in the drill pipe.

The annulus within which the piston 10 and third sleeve 7 move, isuppermost defined by the end piece 13 and lowermost by an externalannular portion 22 of first sleeve 1. The annular portion 22 is assigneda radial bearing 23 rotatably mounting first sleeve 1 within secondsleeve 2. An axial bearing 24 within the annulus between the sleeves 1,2 below the annular portion 22, rests against the end of a bearingsleeve 25 screwed into the lower end of second sleeve 2, forming a fixedcontinuation thereof, second sleeve 2 and bearing sleeve 25 beingprovided with threads 26. A downwardly directed axial force in firstsleeve 1 is, thus, accommodated by the axial bearing 24, the bearingsleeve 25 and second sleeve 2. An annular packer 27 seals between firstsleeve 1 and the bearing sleeve 25, and an annular packer 28 sealsbetween the bearing sleeve 25 and second sleeve 2. A radial bearing 29provides rotatable mounting of first sleeve 1 in the bearing sleeve 25.At the lower end thereof, first sleeve 1 is rigidly and pressure-tightlyconnected to a lower end piece 30 through threads 31 and packers 32, 33.Uppermost, the and piece 30 is provided with a graduation passed intothe lower end of the bearing sleeve 25. An axial bearing 34 is placedbetween the upper edge of the end piece 30 and an internal shoulder 35in the bearing sleeve 25. An upwardly directed axial force in firstsleeve 1 is, thus, transferred from the end piece 30 to the bearingsleeve 25 and to second sleeve 2. As previously known, the lower part ofthe end piece 30 is provided with threads 36 for coupling thereto adrilling equipment or well equipment, not shown.

In the bearing sleeve 25, a radial threaded hole 37 is disposed, forattaching a grease nipple, not shown, allowing grease to be squeezedinto the radial bearing 29 and the axial bearing 35. When theorientation device is in use, the hole 37 is sealed by means of athreaded plug, not shown.

In second sleeve 2, adjacent the radial bearing 23 and the axial bearing24, a threaded hole has been disposed, in order to vent the annulus inwhich the piston 10 and third sleeve 7 are situated. When theorientation device is in use, said hole is sealed by a of a threadedplug.

What is claimed is:
 1. An orientation device for drilling tools or wellequipment in oil or gas wells, which device comprises:a first sleeve andan axially displaceable carrier adapted to slide in an inclined grooveformed in said first sleeve, the direction of said groove crossing thedirection of rectilinear movement of said carrier, the rectilinearmovement being converted into rotational movement of said first sleeve;and a second sleeve concentric with said first sleeve, said secondsleeve formed with a crossing groove into which the carrier also engagesslidingly.
 2. An orientation device as set forth in claim 1 wherein saidcarrier is a wedge or key.
 3. An orientation device as set forth inclaim 1 wherein said carrier is a rail.
 4. An orientation device as setforth in claim 1 wherein said carrier is moved by an operating rod. 5.An orientation device as set forth in claim 1 wherein said first sleeveand said second sleeve inclined grooves are helical.
 6. An orientationdevice as set forth in claim 5 wherein said first sleeve helical grooveextends in an opposite helical direction from said second sleeve helicalgroove.
 7. An orientation device as set forth in claim 1 wherein saidcarrier rotates, both said first and said second sleeve.
 8. Anorientation device as set forth in claim 1 including a third sleevedisposed between said first and second sleeve and coaxial with saidfirst and second sleeve.